UITextView中带有换行的exclusionPaths错误

当textView具有换行符时，exclusionPaths存在问题：

这是我的代码：

- (void)viewDidLoad
{
  [super viewDidLoad];
  UIView *view = [[UIView alloc] init];
  UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(0, 333, 360, 480)];
  view.frame = CGRectMake(50, 0, 50, 50);
  view.backgroundColor = [UIColor blackColor];
  NSLog(@"%@", NSStringFromCGRect(view.frame));
  [textView addSubview:view];

  CGRect relativeRect = [textView convertRect:view.bounds fromView:view];

  UIBezierPath *bezierPath = [UIBezierPath bezierPathWithRect:relativeRect];
  textView.text = @"asddsaadasddsasdasdjsdhfjkdhkjdhfgjkldhsgfjlk\n\nhfdsgjklhdfsljkghdklfjgshdgjklfshdfgjklhfglkjdshjklgfdshjklgdfshkljfdsghfjkldghlkjfdghskljgdfhslkjgdfshjklgfdshjkgfdshlkjgdfhskljdgfhsjklgdhsjklfgdshjkglfdshjklgfdshlkjfgdhjklgdfshjdfkslghkjfdlsghjkldsfghjkhdfsgkjlhjgkldfshgdflksjhfdksgjhdfkjlgshfkljdshgjkdfhskjglhdfsjkghdfkjglhdsfkjghkljdfhgkjlhdsfkjlghjkldsfghjklhgsfdjklhgsdfkjlghdsfklgfdhsklg";
  textView.textContainer.exclusionPaths = @[bezierPath];
  [self.view addSubview:textView];

}

结果如下：

问题在于换行符使exclusionPaths超出其应有的大小。在此处还描述了该问题：iOS 7 UITextView中的换行符打破了文本工具包排除区域的环绕，但它显示了如何使用Interface Builder创建UITextView时解决此iOS 7错误。如何以编程方式解决此问题？谢谢！